Solvent/non-solvent treatment as a method for surface coating of poly(ε‑caprolactone) 3D-printed scaffolds with hydroxyapatite

Introduction Over the last decades numerous new materials and techniques for bone tissue engineering have been developed. The use of bioresorbable polymeric scaffolds is one of the most promising techniques for surgical management of bone defects. However, the lack of bioactive properties of biodegradable polymers restricts the area of their application for bone tissue engineering. The aim of study was to apply solvent/non-solvent treatment to coat the surface of 3D-printed bioresorbable poly(ε-caprolactone) scaffolds with bioactive hydroxyapatite particles and report on the physicochemical properties of the resulting materials. Material and Methods In the present study, biomimetic poly(ε-caprolactone) scaffolds were 3D-printed via fused deposition modeling technology and their surface was treated with the solvent/non-solvent method for coating with bioactive particles of hydroxyapatite. Results It has been found that treatment in the mixture of toluene and ethanol is suitable for the coating of poly(ε‑caprolactone) scaffolds with hydroxyapatite. The scaffolds maintain porous structure after treatment while hydroxyapatite particles form homogeneous coating. The amount of hydroxyapatite on the treated scaffolds was 5.7 ± 0.8 wt. %. Discussion The proposed method ensures a homogeneous coating of outer and inner surfaces of the poly(ε-caprolactone) scaffolds with hydroxyapatite without a significant impact on the structure of a scaffold. Fourier-transform infrared spectroscopy confirmed that the solvent/non-solvent treatment has no effect on the chemical structure of PCL scaffolds. Conclusion Coating of biomimetic 3D-printed PCL scaffolds with bioactive hydroxyapatite by the solvent/non-solvent treatment has been successfully carried out. Upon coating, scaffolds retained their shape and interconnected porous structure and adsorbed hydroxyapatite particles that were uniformly distributed on the surface of the scaffold.